Many projects within the Northeast Biodefense Center application require high-quality purified recombinant proteins and pseudotyped virus for their research. The goal of the Protein Expression Core is to facilitate the investigative, developmental, and pilot studies proposed in the various themes of this application. The staff of the Core will assist investigators in the translation of their studies to quality controlled standard assays, vaccines or therapeutics. Staff will work with investigators to develop expression systems for the proteins required for their studies either using commercial vectors or customized expression vectors. The facility will provide a complete protein expression and purification service. This will include access to well established bacterial expression capabilities at the Wadsworth Center; specialized capabilities exploiting mammalian, insect expression, and in vitro translation at the Albert Einstein College of Medicine; and the production of specially designed pseudotyped VSV viruses that greatly facilitate analysis of neutralizing antibodies at Yale University. These three service components, headed by experts within their field, will allow the rapid provision of reagents for research projects and provide the NBC with the flexibility to support the wide range of existing needs and to respond rapidly to the changing requirements of principal investigators and changing NIAID mandates. In addition, the Core will maintain stable stocks of proteins and expression strains so that in a time of emergency, production of these materials will be rapid.